After equaling the all-time record for victories in a major league season with 116, Seattle found itself facing a must-win situation after dropping the series opener Tuesday.
The Mariners responded by scoring all their runs on homers and Moyer continued the form he displayed during the latter part of the season to send the series to Cleveland deadlocked at 1-1.
Game 3 in the best-of-five series will be played Saturday.
Chuck Finley made the start for Cleveland, his first playoff appearance since he was a rookie with the Anaheim Angels 15 years ago. But before he could retire a batter, he faced a four-run deficit
Finley walked Ichiro Suzuki to open the Seattle first and Cameron, who was one for 17 against the Cleveland starter, sent an 0-2 pitch into the left-field seats.
"I left a fastball over the plate to Cameron," Finley said. "I was trying to come in, but I didn't get it in enough. He got the ball out in front and hit it pretty good."
That brought up Bret Boone, who produced a sharp single up the middle and Martinez crushed the first pitch he saw over the center-field wall.
"I couldn't really tell where that pitch was," Finley said. "It was away a little bit and I didn't really think he hit it that good. I was kind of surprised he got on that ball pretty good. Usually he is a more patient hitter, but he was up there hacking."
Staked to a quick lead, Moyer did not allow a hit until the fourth and went six plus innings before being removed when Ellis Burks and Jim Thome opened the seventh with singles.
Jeff Nelson came on and walked Travis Fryman to load the bases with none out. But Marty Cordova grounded into a double play, on which Buerks scored, and Einar Diaz flew out to center to end the inning and the Indians' final threat.
Seattle's fifth run came on a leadoff homer by David Bell in the fifth.
Moyer went 11-1 with a 2.27 ERA in his final 14 starts this season and won both his starts against Cleveland, allowing just one run in 14 innings. He surrendered five hits Thursday with one walk and four strikeouts. At age 38, he became the oldest pitcher in major league history to record 20 victories for the first time.
After Nelson worked out of the seventh-inning problems, Seattle manager Lou Piniella called on his 1-2 closeout punch from the bullpen. Arthur Rhodes pitched a perfect eighth and Kazuhiro Sasaki allowed a one-hit single but struck out two in the ninth to close it out.
"That was vintage Jamie," Piniella said. "We wanted to keep his pitch count low, just in case he has to come back on three days' rest on Monday. He gave us exactly what we needed."
"This was a dream come true," Moyer said. "It was a team effort and we played well together today. And I expect we'll go to Cleveland and have the same results."
Finley, who has beaten the Mariners 19 times in his career, was tagged for five runs and five hits in 4 1/3 innings. He walked two and struck out three.
"What happened to him was exactly what we did not want to happen," Indians manager Charlie Manuel said. "He made two mistakes -- the home runs were mistakes. We fell behind, 4-0, and after that, Moyer settled in and pitched a good game."
"I had a chance to do some good things today," Finley said. "You wait a long time to do it and it turns out like this. I've got to hope I will get a chance to go out and try it again."
The Mariners will send will send 15-game winner Aaron Sele to the mound Saturday. The Indians will counter with 21-year-old lefthander C.C. Sabathia, who won 17 games as a rookie.
"It was as close to a must-win game as you want to be," Piniella said. "You don't want to lose two ballgames at home and go to your opponent's ballpark and have to win two and come back here. We've tied the series now. Now it's down to two out of three."